Apparatus and method for the disposal of liquid waste material

ABSTRACT

An incinerator and method for the disposal of liquid waste material containing a substantial amount of water. The incinerator comprises a hollow shell having an inclined elliptically shaped thermally conductive baffle plate having a plurality of openings therethrough. The baffle plate is mounted at an oblique angle inside of the shell, dividing the latter into two portions. Liquid waste material is sprayed through a nozzle onto the upper surface of the baffle plate while a fuel-fired flame is directed against the lower surface of the baffle plate. Water is rapidly evaporated and combustible components of the liquid waste material are burned, the water vapor and combustion products passing into the atmosphere through a flue.

United States Patent [151 3,698,331 Rohr et a1. Oct. 17, 1972 [5APPARATUS AND METHOD FOR THE 3,572,265 3/1971 Stockman ..110/18 DISPOSALOF LIQUID WASTE MATERIAL Primary Examiner-Kenneth W. Sprague [72]Inventors: Alton J. Rohr, Framingham; Cor- Attorney Harry Saragovltz et11:22:: J. McKeown, Natick, both of [57] ABSTRACT [73] Assignee: TheUnited States of America as n incinerator and method for the disposal ofliquid represented by the Secretary of the waste material containing asubstantial amount of Army water. The incinerator comprises a hollowshell having an inclined elliptically shaped thermally conductive FllediJ y 1971 baffle plate having a plurality of openings [21] Appl No;163,794 therethrough. The baffle plate is mounted at an oblique angleinside of the shell, dividing the latter into two portions. Liquid wastematerial is sprayed 1 Cell. ..110/7 2 2510512: through a nozzle omo theupper surface of the harm ll. g It f fi fl td inst th paew eaue e aesrece aga e [58] held 8 8 Is 18 C lower surface of the baffle plate.Water is rapidly References Cited evaporated and combustible componentsof the liquid waste material are burned, the water vapor and combustionproducts passing into the atmosphere through a flue.

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APPARATUS AND METHOD FOR THE DISPOSAL OF LIQUID WASTE MATERIAL back ofthe front lines. They require sanitary facilities for these groups, suchas batteries of shower baths, lavatories, and latrines to service groupsof up to about 250 men. This poses a problem of disposing of up to about100 gallons of urine per day and, with an equal quantity of flushingwater added, a total of up to about 200 gallons per day of diluted urinefor a group of 250 men. Without sewage disposal plants, such as arecommon in most developed areas, it has become important for militaryoperations in the field that sanitation facilities be provided includingequipment for disposing of liquid waste materials, such as urine,substantially as fast as it is accumulated in storage tanks connected tothe latrines.

Accordingly, an object of the invention is to provide an improvedincinerator for the disposal of liquid waste material containing asubstantial amount of water.

Another object is to provide a method for sanitarily disposing of liquidwaste material containing a substantial amount of water.

Other objects and advantages of the invention will become apparent fromthe following description of the invention, and the novel features willbe particularly pointed out in connection with the appended claims.

In the accompanying drawings:

FIG. 1 is a side elevation of the incinerator of the invention;

FIG. 2 is a vertical section through the incinerator along the line 2-2in FIG. 1 looking toward the end of the incinerator in which a burner ismounted, and showing a baffle plate mounted in the incinerator; and

FIG. 3 is a plan view of the baffle plate looking at the upper surfacethereof.

In the illustrated embodiment of the invention, the incinerator 10comprises a hollow shell 11 in which the liquid waste material 12, whichis sprayed into the shell by spray nozzle 13, is evaporated and burned.The liquid waste material in fine spray form impinges on the uppersurface of baffle means 14, most of the spray striking the top portionof the baffle means because of the upward tilt of the spraynozzleJHowever, a portion of the spray also strikes the inside surfaceof the top of the shell between flue stack 15 and the baffle means toprevent the top of the shell from being overheated by the flame 16produced inside of the shell by fuel-fired burner 17, which ispreferably fired with oil.

Baffle means 14 is preferably a thermally conductive plate made ofcorrosion resistant material, such as a corrosion-resistant metal oralloy, having a plurality of spaced openings 18 passing therethroughfrom the upper surface to the lower surface thereof for the flame fromthe fuel-fired burner to pass through on its way to flue stack 15. Thebaffle plate is preferably elliptical in outline shape. This enablestilting of the baffle plate so that an included angle of about is formedbetween the upper surface of the baffle plate and the top of the shell.Thus the interior of the shell is divided into two distinct portions bythe baffle plate, namely a burner portion 19 and a nozzle portion 20.The baffle plate is supported by a pin 21 mounted in the top of theshell against which the baffle plate rests, a rod 22 mountedhorizontally in the shell about midway between the top and bottom of theshell, the rod preferably being welded at each end thereof to a sidewallof the shell, and a bracket 23 releasably held against the lower end ofthe baffle plate by a wing bolt 24 which is screwed into nut 25, thelatter being welded to the bottom of the shell. The baffle plate isreadily removable from the shell for purposes of cleaning out theincombustible ash that drops to the bottom of the shell. This isaccomplished by unscrewing the wing bolt 24 and lifting the baffle plateout of the shell through the nozzle portion thereof after removal of theend plate 26 from the shell which is made possible by unscrewing bolts27.

As illustrated by FIG. 3, the elliptically shaped baffle plate has anangle iron 28 welded to the upper surface of the baffle plate along thelong axis of the baffle plate. This angle iron provides support to thebaffle plate to prevent its being warped by the approximately 2,000F.temperature developed in he baffle plate by the flame. The fine spray ofliquid waste material impinging on the baffle plate is rapidly heated bythe baffle plate as well as by the flame and combustion products fromthe oil burner which pass through the spaced openings in the baffleplate and deliver heat to the droplets in the fine spray of liquid wastematerial in the nozzle portion of the shell adjacent to or in thevicinity of the baffle plate. Rapid evaporation of the water in theliquid waste material occurs, the water vapor being conducted into theflue stack 15 and any extension thereof by the hot combustion productsand thence into the external atmosphere. Any combustible solids presentin the liquid waste material are burned, contributing additional heatand combustion products to those derived from the fuel. Anyincombustible materials, such as salts and metal oxides, drop to thebottom of the shell and must be cleaned out periodically, as describedabove.

The baffle plate for use in the disposal of urine may be made of any ofa large number of corrosion resistant metals or alloys, among which arethe Hastelloys. However, it is preferably made of Inconel 600, l 1 gage(0. l 25 inch thick), having six one-fourth inch diameter openings persquare inch therethrough, the openings being on 7/ 16-inch staggeredcenters, with an open area of about 30 percent of the total area of eachof the upper and lower surfaces of the baffle plate. A metal plateproduct manufactured by Ferguson Perforating & Wire Co., Providence, R].has these characteristics. If the baffle plate were constructed ofappreciably heavier gage material, it would be possible to dispense withthe angle iron 28, which gives support to the baffle plate. However,this would appreciably increase the cost of the baffle plate, which mustbe constructed of corrosion-resistant material because of thecorrosiveness of urine, particularly at elevated temperatures.

The angle at which the baffle plate is inclined with respect to the topof the shell is selected so that any of the liquid waste material thatimpinges on the baffle plate in the liquid state will flow by gravityalong the solid portions of the upper surface of the baffle plate andwill not drop off the baffle plate into the bottom of the shell. It ispreferred that this angle be about 60. If the angle is much greater than60, the spray of liquid waste material is likely to pass through theopenings in the baffle plate to too great an extent and cause the flameto be extinquished by too rapid cooling of the fuel vapors. If the angleis much less than 60, the liquid waste material which impinges on thebaffle plate may flow down through the openings in the baffle plate anddrop off before the water has absorbed enough heat to cause evaporationthereof.

The openings through the baffle plate are of such diameter and spacedapart so that it is very unlikely that the spray of liquid wastematerial will pass through the baffle plate and cool the fuel vapors tosuch an extent as to extinquish the flame.

The rate of flow of fuel and the rate of flow of the liquid wastematerial must be maintained within close limits if efficient disposal ofthe liquid waste material is to be accomplished. It has been found to bebetter to use too much fuel rather than not enough since in the lattercase liquid waste material will not be heated fast enough and will flowby gravity down the baffle plate to the bottom of the shell and will,therefore, necessitate too frequent cleaning out of the incinerator.Furthermore, the cleaning of the incinerator will be much more difficultif large amounts of the liquid waste material have been allowed to flowdown or drip off of the baffle plate to the bottom of the shell. On theother hand, if a large excess of fuel is used over that required toevaporate and burn the liquid waste material as rapidly as it is sprayedinto the incinerator, the incinerator will become overheated, creatingproblems of distortion of the metal parts thereof. it has been found tobe desirable to incinerate diluted urine at a rate of about 8 gallonsper hour employing a back pressure of about 18 to 20 p.s.i. ln order todo this, it has been found best, when using fuel oil in the fuel burner,to operate the burner at a flow rate of about 1.5 gallons of fuel oilper hour and not to allow the fuel oil to impinge on the baffle plate.When the supply of urine in the storage tank (not shown) decreases to apredetermined low level, the burner ceases to operate but the urine pump(not shown) continues operating for about 20 seconds, forcing urine intothe incinerator. When the urine flows into the storage tank and reachesa predetermined level, the burner is started again to preheat theincinerator. After about 50 seconds, the pump is turned on and sprayingof urine into the incinerator is resumed, both fuel oil and urine beingpumped at the above-described flow rates. The urine pump is permitted tocontinue operating for a short time after the burner is shut off toprovide cooling of the incinerator. The burner is started before theurine pump after a shutdown in order to avoid accumulations ofunevaporated and unburned urine in the bottom of the incinerator shell.

In general, a high temperature in the incinerator is desirable in orderto maintain the temperature of the exhaust gases in the flue stack at ahigh level since the escape of odors into the surrounding atmosphere isminimized under these conditions.

If it is desired to vary the rate of fuel flow, it is necessary in orderto obtain the best results to vary the positioning of the baffle plate.The higher the flow rate of the fuel, the farther removed the baffleplate should be from the burner nozzle; vice versa, the lower the flowrate of the fuel, the nearer the baffle plate should be to the burnernozzle.

The spray nozzle for spraying urine on the baffle plate is preferably amodel H2B Spraco nozzle, manufactured by Spray Engineering Co.,Burlington, Mass. This type of nozzle produces a hollow cone-shapedspray pattern, the droplets being quite fine. However,,it is best not touse a nozzle which produces too fine a spray since, in such a case, someof the extremely fine droplets of urine are carried out the flue stackwithout evaporating and burning.

In order to keep the incinerator of the invention operating as smoothlyas possible with a minimum number of interruptions, it has been foundthat the addition of about 1 pint of 5 percent hypochlorite bleachsolution to the supply of urine in the storage tank twice a dayeliminates plugging of the filter and the building up of a precipitateof calcium magnesium phosphate on the pump impeller to such an extent asto cause jamming of the pump. The calcium magnesium phosphate resultsfrom the action of microorganisms on the urine. Thus, the hypochloritekeeps in check the growth of microorganisms in the urine and eliminatesthe precipitation of calcium magnesium phosphate in critical parts ofthe liquid waste disposal apparatus.

The incinerator and method of the present invention are very useful indisposing of liquid waste materials, such as urine, by evaporation ofthe water therein and combustion of the combustible components thereofand elimination of the evaporated components and combustion productsinto the atmosphere. This avoids contamination of streams in thevicinity of concentrations of troops in military operations where normalsewage handling facilities are not available. Advantages include bettersanitation since the high temperatures employed in the incineratordestroy all microorganisms present in the liquid waste material.

It will be understood that various changes in the details, materials andarrangements of parts which have been herein described and illustratedin order to explain the nature of the invention, may be made by thoseskilled in the art within the principle and scope of the invention.

We claim:

1. In an incinerator for the disposal of liquid'waste materialcontaining a substantial amount of water comprising a hollow shellwherein said liquid waste material is evaporated and burned, thecombination of a burner means for directing a fuel-fired flame into saidshell from a first end thereof, a spray nozzle means for directing afine spray of said liquid waste material into said shell from the otherend thereof, a flue means for conducting evaporated components andcombustion products from said liquid waste material and said flame outof said shell, and a baffle means positioned in said shell between saidburner means and said spray nozzle means, said baffle means comprising athermally conductive plate having a plurality of spaced openingstherethrough and being disposed within said shell to provide an inclinedupper surface facing said spray nozzle means such that liquid wastematerial impinging on said upper surface will flow by gravity along saidupper surface, said spray nozzle means being adapted to direct said finespray of liquid waste material upon the inclined upper surface of saidbaffle means, said burner means being adapted to direct said flameagainst the lower surface of said baffle means, whereby the heat fromsaid flame is transferred to said liquid waste material on and in theproximity of the upper surface of said baffle means to evaporate theaqueous portions of said liquid waste material and to burn thecombustible portions of said liquid waste material.

2. A combination as set forth in claim 1, wherein said shell is in theform of a cylinder, the central axis of said cylinder being in asubstantially horizontal plane.

3. A combination as set forth in claim 2, wherein said baffle means is agenerally elliptically shaped plate conformed to substantiallycompletely divide the interior of said shell into two portions.

4. A combination as set forth in claim 3, wherein the included angleformed between the upper surface of said baffle plate and the top ofsaid shell is about 60.

5. A combination as set forth in claim 3, wherein said spaced openingsare generally circular and spaced apart substantially equidistantly, thetotal areas of said openings being about 30 percent of the total surfacearea of said upper surface and of said lower surface of said baffleplate.

' 6. A combination as set forth in claim 4, where said spray nozzlemeans is adapted to produce a hollow cone-shaped spray.

7. A combination as set forth in claim 6, wherein said spray nozzlemeans is directed upward from the horizontal to direct said spray towardthe top portion of the upper surface of said baffle plate and toward theinternal surface of the top portion of said shell adjacent to the uppersurface of said baffle plate.

8. In a method of disposing of liquid waste material containing asubstantial amount of water which is characterized by spraying saidliquid waste material into the interior of a shell and directing aliquid fuelfired flame into said interior of said shell to evaporate theaqueous portions of said liquid waste material and to burn thecombustible portions of said liquid waste material, the improvementwhich comprises spreading said liquid waste material on a first surfaceof a perforated baffle plate and directing said flame on the surface ofsaid perforated baffle plate opposite to said first surface, whereby theheat from said flame is more efficiently transferred to said liquidwaste material than in the absence of said perforated baffle plate.

9. In a method as set forth in claim 8, wherein said spreading of saidliquid waste material on said first surface of said perforated baffleplate is carried out by spraying said liquid waste material on saidfirst-surface of said perforated baffle plate.

10. In a method as set forth in claim 9, where said spraying of saidliquid waste material is carried out at a flow rate of about 8 gallonsper hour at a back pressure of from about 18 to about 20 pounds persquare inch and said flame is produced by fuel oil at a flow rate ofabout 1.5 gallons per hour.

1. In an incinerator for the disposal of liquid waste materialcontaining a substantial amount of water comprising a hollow shellwherein said liquid waste material is evaporated and burned, thecombination of a burner means for directing a fuelfired flame into saidshell from a first end thereof, a spray nozzle means for directing afine spray of said liquid waste material into said shell from the otherend thereof, a flue means for conducting evaporated components andcombustion products from said liquid waste material and said flame outof said shell, and a baffle means positioned in said shell between saidburner means and said spray nozzle means, said baffle means comprising athermally conductive plate having a plurality of spaced openingstherethrough and being disposed within said shell to provide an inclinedupper surface facing said spray nozzle means such that liquid wastematerial impinging on said upper surface will flow by gravity along saidupper surface, said spray nozzle means being adapted to direct said finespray of liquid waste material upon the inclined upper surface of saidbaffle means, said burner means being adapted to direct said flameagainst the lower surface of said baffle means, whereby the heat fromsaid flame is transferred to said liquid waste material on and in theproximity of the upper surface of said baffle means to evaporate theaqueous portions of said liquid waste material and to burn thecombustible portions of said liquid waste material.
 2. A combination asset forth in claim 1, wherein said shell is in the form of a cylinder,the central axis of said cylinder being in a substantially horizontalplane.
 3. A combination as set forth in claim 2, wherein said bafflemeans is a generally elliptically shaped plate conformed tosubstantially completely divide the interior of said shell Into twoportions.
 4. A combination as set forth in claim 3, wherein the includedangle formed between the upper surface of said baffle plate and the topof said shell is about 60*.
 5. A combination as set forth in claim 3,wherein said spaced openings are generally circular and spaced apartsubstantially equidistantly, the total areas of said openings beingabout 30 percent of the total surface area of said upper surface and ofsaid lower surface of said baffle plate.
 6. A combination as set forthin claim 4, where said spray nozzle means is adapted to produce a hollowcone-shaped spray.
 7. A combination as set forth in claim 6, whereinsaid spray nozzle means is directed upward from the horizontal to directsaid spray toward the top portion of the upper surface of said baffleplate and toward the internal surface of the top portion of said shelladjacent to the upper surface of said baffle plate.
 8. In a method ofdisposing of liquid waste material containing a substantial amount ofwater which is characterized by spraying said liquid waste material intothe interior of a shell and directing a liquid fuel-fired flame intosaid interior of said shell to evaporate the aqueous portions of saidliquid waste material and to burn the combustible portions of saidliquid waste material, the improvement which comprises spreading saidliquid waste material on a first surface of a perforated baffle plateand directing said flame on the surface of said perforated baffle plateopposite to said first surface, whereby the heat from said flame is moreefficiently transferred to said liquid waste material than in theabsence of said perforated baffle plate.
 9. In a method as set forth inclaim 8, wherein said spreading of said liquid waste material on saidfirst surface of said perforated baffle plate is carried out by sprayingsaid liquid waste material on said first surface of said perforatedbaffle plate.
 10. In a method as set forth in claim 9, where saidspraying of said liquid waste material is carried out at a flow rate ofabout 8 gallons per hour at a back pressure of from about 18 to about 20pounds per square inch and said flame is produced by fuel oil at a flowrate of about 1.5 gallons per hour.